Real-time satellite communication system using separate control and data transmission paths

Claim 1

A control communication method for a satellite communication system having a central earth station and a plurality of remote earth stations linked to the central earth station through at least one satellite in orbit above the earth, the method comprising: synchronizing a timing in the central earth station and the plurality of remote earth stations such that a predetermined control time period having a plurality of distinct sequential time slots is synchronized among the central earth station and the remote earth stations; initiating from a respective remote earth station, and completing, a transmission of control information through the satellite to the central earth station only during a respective one or more of the time slots assigned to the respective remote earth station; receiving the transmission at the central earth station; and sending from the central earth station, in response to the received transmission, a separate transmission of data through the satellite to the remote earth station; determining a substantially real-time response time period for the respective central earth station and remote earth stations, wherein the control time period is not longer than the substantially real-time response time period; and determining the number of time slots that can be assigned to remote earth stations for the control time period that is not longer than the determined substantially real-time response time period.

Claim 14

A method of providing information to remote locations, comprising: defining a satellite communication group having a central earth station, a plurality of remote earth stations each at a respective location remote from the central earth station, and a satellite in orbit above the earth, wherein the satellite has a predetermined communication bandwidth; assigning a cyclical control communication time period to the defined satellite communication group, wherein the control communication time period is not longer than a substantially real-time response time period for any one of the remote earth stations in the defined satellite communication group; determining a transmission time having a duration sufficient for a transmission to be sent from any of the remote earth stations and received by the central earth station; allocating a specific number of time slots within the control communication time period in response to the duration of the control communication time period and the determined transmission time; determining the number of remote earth stations in the defined satellite communication group and the number of time slots; assigning each remote earth station to at least one respective time slot and to a common control transmission frequency if there are not more remote earth stations than time slots; if there are more remote earth stations than time slots, assigning a remote earth station to at least one respective time slot and continuing such assigning for other remote earth stations until the time slots are all allocated and assigned a first common control transmission frequency to these assigned remote earth stations, and allocating other remote earth stations to respective time slots but at a second common control transmission frequency and repeating the same for additional remote earth stations and respective common control transmission frequencies until all the remote earth stations are assigned at least one respective time slot and common control transmission frequency; time synchronizing the central earth station and the plurality of remote earth stations such that the cyclical control communication time period is synchronized among the central earth station and the remote earth stations; initiating from a respective remote earth station, and completing, a transmission of control information through the satellite to the central earth station only during a respective one or more of the time slots of the cyclical control communication time period assigned to the respective remote earth station; receiving the transmission at the central earth station; and sending from the central earth station, in response to the received transmission, a separate transmission of data through the satellite to the respective remote earth station.

Claim 15

A method of providing information to remote locations, comprising: defining a satellite communication group having a central earth station, a plurality of remote earth stations each at a respective location remote from the central earth station, and a satellite in orbit above the earth, wherein the satellite has a predetermined communication bandwidth; assigning a cyclical control communication time period to the defined satellite communication group, wherein the control communication time period is not longer than a substantially real-time response time period for any one of the remote earth stations in the defined satellite communication group; determining a transmission time having a duration sufficient for a transmission to be sent from any of the remote earth stations and received by the central earth station; allocating a specific number of time slots within the control communication time period in response to the duration of the control communication time period and the determined transmission time; determining the number of remote earth stations in the defined satellite communication group and the number of time slots; assigning each remote earth station to at least one respective time slot and to a common control transmission frequency if there are not more remote earth stations than time slots; if there are more remote earth stations than time slots, assigning a remote earth station to at least one respective time slot and continuing such assigning for other remote earth stations until the time slots are all allocated and assigned a first common control transmission frequency to these assigned remote earth stations, and allocating other remote earth stations to respective time slots but at a second common control transmission frequency and repeating the same for additional remote earth stations and respective common control transmission frequencies until all the remote earth stations are assigned at least one respective time slot and common control transmission frequency; time synchronizing the central earth station and the plurality of remote earth stations such that the cyclical control communication time period is synchronized among the central earth station and the remote earth stations; initiating from a respective remote earth station, and completing, a transmission of control information through the satellite to the central earth station only during a respective one or more of the time slots of the cyclical control communication time period assigned to the respective remote earth station; receiving the transmission at the central earth station; and sending from the central earth station, in response to the received transmission, a separate transmission of data through the satellite to the respective remote earth station.